1. Field of Invention
The present invention relates to track vehicles. In particular, it relates to a track vehicle employing a rail track system, which provides lighter more even ground contact for use on snow and other soft terrain than present track vehicles.
2. Description of Related Art
Various track vehicles to provide ground propulsion with endless crawler track are known. Tani et al, U.S. Pat. No. 6,199,646B1 discloses a working vehicle with semi-crawler units associated with propelling drive shafts. Each semi crawler unit includes a drive rolling element attachable to one of the propelling drive shafts, an endless crawler track driven by two front and rear and a large central drive rolling elements to contact the ground for vehicle propulsion. These drive rolling elements provide increased pressure point contacts where the track contacts the ground. Chhabra et al, U.S. Pat. No. 6,179,073B1, discloses a hybrid track for a track vehicle incorporating dual tracks each having a plurality of rollers such that the axis of the rollers of each track are in a normal V alignment with those of a corresponding dual track. Gignac, U.S. Pat. No. 6,125,956 discloses a vehicle on tracks driven by toothed wheels mounted to the front and back of each side to drive the tracks, and including two pivoting dual wheel suspension tandems mounted to the middle segments of the frame to uniformly extend the track to contact the ground along four points. Miyaki et al, U.S. Pat. No. 5,927,413 discloses a crawler belt drive apparatus for crawler type vehicles employing a plurality of links, and a link guide such that the links are driven by a drive sprockets associated with a drive shaft at each end of the vehicle; said belt extended to contact the ground via a plurality of rollers attached to the frame and employing link guide muting means to reduce meshing noises and vibrations of the crawler belt. Gustin et al., U.S. Pat. No. 5,494,125 discloses a track supporting roller apparatus employing a plurality of bogie arms and a plurality of track supporting rollers rotatably connected to the bogie arms specifically spaced with respect to track pitch to reduce vibration and shock loads. Lagasse, U.S. Pat. No. 5,388,656 discloses an endless belt traction device for the road wheel of a farm tractor or analogous vehicle employing three wheels about which an endless flexible belt is trained. Gilbert, U.S. Pat. No. 5,343,960 discloses a caterpillar track attachment for a wheeled vehicle having a drive shaft and an hydraulic steering mechanism to convert said vehicle from wheeled drive to continuous track drive. James, U.S. Pat. No. 4,950,211 discloses a track drive sprocket wheel for snow grooming vehicles wherein the sprocket wheel has an enlarged toothed flange providing improved guiding contact with the grousers and utilizing contact with typical non-pneumatic tire guides to increase belt stability and reduce grouser and belt stresses, as well as to increase sprocket wheel durability. Davin et al., U.S. Pat. No. 3,776,326 disclosing an asphalt paving machine mounted on continuous rubber tread tracks mounted around bogie wheels along the sides of the vehicle, and a track tension wheel at one end of the vehicle and a drive sprocket at the other end of the vehicle to drive the tracks. Triplett, U.S. Pat. No. 4,519,465 discloses a variable width extension track type four sprocket wheel drive for crawler tractors using hydraulic pumps and motors for propulsion. Schoonover, U.S. Pat. No. 3,717,214 discloses a tracked vehicle walking beam assembly with equalizing means for ground pressure and track length employing a sprocket-driven, endless track. The equalizing means for equalizing variations in ground pressure and track length has a walking beam pivotally mounted on the shaft with bogey wheels, in between which are backup idler rollers to protect the walking beam when the track passes over obstacles in the area between the bogey wheels. Mosshart et al, U.S. Pat. No. 3,736,032 discloses a pneumatic drive sprocket for tracked vehicles which includes a belted radial tire casing having radially projecting lugs or teeth disposed in spaced-apart relationship about the circumference of the tire and which are adapted to engage the track for driving purposes. Smith et al., U.S. Pat. No. 5,361,860 discloses another continuous belt drive conversion unit for wheel driven tractors.
The present invention described below provides a vehicle with a continuous track system employing a plurality of spaced triangular torsion compression links with an end adapted to run along a track running the length of the vehicle and the other wheel ends adapted to extend the track to provide multiple contact points and uniform extension of the tracks.